|Sheaffer, Craig - UNIVERSITY OF MINNESOTA|
|Christians, Charles - UNIVERSITY OF MINNESOTA|
|Head, William - UNIVERSITY OF MINNESOTA|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 20, 1999
Publication Date: N/A
Technical Abstract: Management intensive grazing increases efficiency of pasture utilization but may increase nitrate leaching. We measured yield and several parts of the N cycle in a 2-yr trial on a Typic Hapludoll soil at St. Paul, MN. Six replicates of established, sole-seeded birdsfoot trefoil (Lotus corniculatus L.) and trefoil-reed canarygrass (Phalaris arundinacea L.) mixtures were either rotationally grazed by ewes or mechanically harvested 4 times each year. Dry matter consumption was about 5.5 Mg/ha for both pasture types. Birdsfoot trefoil competed poorly against weeds and reed canarygrass; it relied more on fixed N in mowed than in grazed plots, and in mixed than in pure legume stands. Significant N transfer to grass occurred under mowing and grazing. Soil inorganic N levels were small except in small areas affected by excreta. Leaching losses from this 0.9-m- deep soil were <5 kg N/ha, regardless of treatment.